Okay, just did some comparisons between the .38 type II, the .44 type II, and a '51 R-M.  The frame and cylinder on all the .38's is the same (which you can tell by parts list numbers as well).  The .38 cylinders measure ~1.63" diameter.  On my oldest 'R-M, it measured 1.61".  1.63" is also the diameter of the rear portion of the .44 cylinder.  I seem to recall looking up in McDowell's book once and the Uberti '51 R-M cylinders are the same as original, as you have also noted.

The .38 frame is not stepped.  So the .44 cylinder will not fit. To get a .44 cylinder to fit on the .38 frame would require milling the front of the water table for the wider portion of the cylinder. The .38 cylinder and barrel fit on the .44 frame, although the frame and barrel would not quite meet at the locator pins, maybe a thousandth or two gap.  I think the arbor was bottoming out in the hole in the barrel.  I could not get the .44 barrel to attach to the '51 frame.  The locater pins "looked" like they lined up, but must have been off the tiniest bit because I couldn't get them started in the holes in the barrel.  Something like a plastic mallet might have made it go on but I didn't want to force anything.

Note too, that the .38 cylinder is shorter than the .44 cylinder, so it has a longer gas seal on the front of it to reach the barrel, and the barrel has a longer extension on the rear (the part where the forcing cone would be).  So, a .38 cylinder on the .44 frame with the .44 barrel attached left a .165" barrel to cylinder gap! 

The two frames both measured .750" wide across the bottom directly in front of the trigger guard, just before the edges are beveled on the bottom.

Regarding your Note 3 - I assume you mean a .44 conversion barrel, since the percussion barrels will not fit the conversions.

Regarding your Note 4 - I was able to trade off the Army grips and frames that came on both of my Type II's for Navy (all Uberti '60 conversions, Type II and R-M, have Army grips regardless of caliber).  You could do the opposite if needed, but if you start with a Type II (or '60 R-M) it will already have Army.  The only Uberti conversion to come with a Navy grip is the '51 (I'm not counting the Opentops, which come with either).

Obviously the '60 conversions never came in .38 back in the day, and just as obviously Uberti likes to make various guns in the more popular calibers of today.  But I don't know why they made their '60 conversions in .38 with the Navy frame/cylinder.  It would have been just as easy to chamber a stepped cylinder in .38 and at least the gun would have LOOKED right, even if the caliber was not authentic.  The '60's with the Navy frame and cylinder just looked wrong.  But fortunately for me, that made it easy to make the '61 conversion.  Charles Hudson at Texas Jacks once opined that Uberti did this so there could actually be a '61 conversion without having to go through the regulatory steps and fees required for acceptance of any "new" product that they come up with.  That may be true, but not many people know about it.  And a '60 R-M in .38, even with a Navy grip, would be a frankengun since Colt never made a Navy conversion with that barrel style.

King,
The photos you provided are not sufficient to make a positive determination based on them alone. It does have the cone shaped firing pin as do all USA parts guns, but need the photos I suggested in my previous post.

I agree with Coffinmaker about not letting a parts gun turn you away, but on the other hand I personally would not pay the price most USFA USA parts guns sell for these days for one built from Italian parts, but that is just me.

I did notice in the photo the cylinder has a turn line or at least a partial turn line. Personally, for me that would hurt its value some.

Ed
Wow........$54.00 for a 25lb. bag of shot now!!! Glad I have at least a couple hundred lbs. stored away from $17.00 a bag. My buddy had 3,000 lbs stored away. Things have just gone sky high  any more.
Macon

Lowering prices one more time before I put them on gunbroker.  Prices include shipping, which costs me $20 - $25.

I'm a bit north of you guys.  We got some wind and a little rain, but that was it despite the "severe thunderstorm warning."  I put the car in the garage for nothing.  Coulda gotten at least a light carwash out of it.