Ah My Good Deacon -
I tottered on over to the appropriate websites to try and come up with a visual and possible answer....
here is a little foto for all of us to illustrate differences

from the picture , there is VERY LITTLE noticable difference between the radius cuts on the frame where the grip safety pins.
the biggest issue, is if what you want is in stock, I guess.
Since Caspian sells only completed frames, ship to FFL, whilst Fusion sells both completed frames and 80% frames
I assumed you were looking at completed frames.
depending on which frame you look at fusion's website states
"This frame can be machined with grip safety tangs (to be used with a conventional GI grip safeties) or a .250" radius cut for more modern beavertail grip safeties. "
https://fusionfirearms.com/parts/frame-parts/framesand a basic complete frame starting at about $170
https://fusionfirearms.com/1911-frame-c-class-government-size"These frames come standard with all of the more modern amenities that today’s 1911 builder desires. Items such as, pre-tapped grip screw bushing holes, precision reamed frame holes, .25” radius beavertail cut, Under-cut trigger guard, Beveled Mag-Well Opening, Matte finished rounds & Ground polished sides and Polished feed ramp."
caspian has these "modern" frames for ~ $215
https://www.caspianarms.com/receiver/modern-receiver-carbonthese "classic" frames for ~ $230
https://www.caspianarms.com/receiver/classic-receiver-carbonand these "with blemishes " for $150
https://www.caspianarms.com/receiver/foster-government-model-receiver-carbon-1Since the grip safety radius difference is so minor, I am not sure it would make any difference at all, but
you best check with the Overlords Of The Rulebook to be sure (none of whom are on this forum...)
yhs
and entertainment specialist
prof marvel