As the OP pointed out the words Fabryka Bronyi Radom which translates to Radom Arms Factory appear on the pistol. The VIS designation is from the initials of the designers Wilniewczyc and Skrzyipinski. (yes, I have noted Wilniewczyc starts with a 'W' - don't ask me)

According to Ian Hogg's 'Military Small Arms of the Twentieth Century' (1973 edition) it is acceptable to refer to the pistol as either a Radom or a VIS. W.H.B. Smith just flat out calls it a Radom.

I haven't held one of these in 20 odd years but they appear to have the VIS insignia on the right grip panel and FB on the left. I'd be interested to find out if this is in fact correct.