FWIW, I personally find the use of the description word "factory" to be problematic. Was the "factory" an IMI, Group Industries, or Vector factory? I have a "factory" full size Uzi - from the Vector factory (built up from a Group Industries registered receiver).
MHO, YMMV, etc.
The word "factory", in any collector market, always refers to the original mass manufacturer during the original production time period. Not whether it was technically made in a factory or not.
Suppose a guy points to the taillights on your 1967 GTO and says, "Are those 'factory'? They look great." The guy is not asking if they were made in a factory, he's asking if they are GM products from 1967. Just because they were technically made in a factory in China for YearOne, doesn't mean they are "factory."
Group and Vector are "clones."
Guns that started life as semi-auto are "conversions."
I have a really nice Vector. It was blueprinted and rewelded by BWE and it runs 100% all the time. But absolutely nobody will ever look at it in the same collector mentality as an original IMI factory gun. It has an interesting back story, but the "historic authenticity" isn't there.
I bought it NIB and even though I am reluctant to shoot NIB collector guns, I burned 1000 rounds with it the first day I got it.
Unless a re-issue or clone or conversion has supremely excellent fit and finish, gun collectors mostly regard them as "shooters." West Hurley Thompsons are excellent ammo burners once you get them running good, but the Thompson collector community regards them to be shooters and absolutely nothing more, even though they were made 50 years ago.
That being said, I love my Vector. I am a shooter and I definitely prefer shooters to minty collector items. A nice compromise is a rebuilt military gun. I have a very nice Thompson M1A1 that was completely rebuilt at Rock Island Arsenal at some point. I bought a couple of NOS barrels and I shoot it all the time. If I burn out a barrel, who cares? It was made in 1944 and all the parts on the gun are USGI, but the originality is zero. Hardcore gun collectors think of a military arsenal rebuild as a complete evaporation of the originality of the gun and call them a "franken gun."
IMI factory UZIs are kind of an oddity, in terms of collecting, because there are so few of them in the NFA registry. I could not tell you how much that shooting an IMI factory gun devalues it, because I've never seen one that looked like it had any use.
That's my 0.02 on it, YMMV.