Jovino
I asked the same question awhile ago and got varying answers from "always" to "not always", truthfully I don't think anyone knows for sure.
I own a 629 stamped Effector that is the real deal because I had it lettered and shipped from S&W to Jovino. I also have a 25 that I just got locally that I believe may be Jovino but waiting for a letter that may prove that it is Jovino. Even if letter comes back.without any ties to Jovino does'nt mean it is'nt just means it was'nt shipped there from the factory.
Around the time Jovino was doing conversion several other smiths were doing similar work. Most conversions are good quality and some were not. What I looked for was how the barrel was cut and crowned, how the front sights were installed and how the grip was converted. Some hack smiths actually cut into the serial number to modify the grip to k frame round.
There are alot of fakes out there so beware. If someone is claiming its a Jovino I would ask for proof. If claiming "Jovino style" or "Jovino like" you know you are getting, a copy.
Copys can be very nice but best to not pay any premium unless you know exactly what it is.
The 25 i bought I paid 700 for not because it was possibly a Jovino but because it was an N frame pre MIM pre lock hand cannon cut down to under 3". If it ends up not being one who cares as it is what it is. Try getting an N frame and a conversion for 700 today, it wont happen.
Good luck.