Centerfire conversion block identification.

[Undertaker18]

Can anyone tell me who made the centerfire conversion block that has an "&" stamped on the top front directly above the groove? 

The gun is an 1860 with serial number 50139. 

[El Supremo]

Hello, Undertaker18:

That mark has been on aftermarket centerfire upper blocks sold by S and S Guns, Glendale NY.  There may have been variations to the internals including either inertia/rebounding firing pins - or not, over many years.
Smiles. 
El Supremo/Kevin Tinny

[Undertaker18]

Thank you.