#1 and #2 I don't have any info on the matter
#3 It is to my understanding that the arsenals that went to the 1.X Million system did so because they did not have the build capacity to justify the extra digit, and they were nothing if not efficient. This would lead me to believe it is likely a less common arsenal.
All matching 1.5 from a lesser common arsenal that you get to put your hands on before buying
at 375 in today's market (especially with no transfer/shipping fees) seems quite reasonable.
You do mention it's worn and I guess the determining factor is, how beat up are we talking here?
But, let the enabler in me also say if I was local I'd be at the shop right now trying to buy it out from under you
GL hope to see pics soon!