I don't know about the US Ordnance brand (is that the original mfg or the company that did the conversion?) but I've got less than the asking dollar value in my semi 1919 with mount. Don't see what would make the gun and tripod worth $4250 in the first place, is there more to this package that you did not list?
I suppose it all depends on whether it is in '06 or 7.62, whether it is all original US parts and how bad you want it.
An original tripod with all the stuff is a bit pricy but in todays market I'm not sure if they are worth all that much.
Firing off a tripod is not the easiest thing with the semi's, not if you want to use the sights, anyway. I ended up getting a pedestal mount for mine, no more lying in the dirt for me!
It is my experience that the accessories for these things are, by far and away, the most costly part of the kit. I've got far more invested in the "stuff" than I do in the firearm.
Now, let's talk ammo, it is real easy to blow through 2 or 3 hundred rounds with one of these (way less than an auto, I know, but still an investment), cheap surplus is gone so you had better be ready to throw some cash at that end of the sport. Don't think that a 20 round box of sporting ammo will do for a range trip, first off it may not function in the gun and, trust me, it will not be enough! Besides, by the time you get finished lugging this beast and all the gear to the range, setting it all up and answering all the questions from the crowd that will gather, it will seem pointless to shoot 20 rounds.
I'm not trying to discourage but these are all things I learned the hard way. In the end, I suppose that $2000 is not out of line but just don't think that the cash outlay ends there, there is always more stuff and supplies that you will want.
I may be of more help if you have specific questions, as I said, I don't know the brand but I'll be happy to share what I do know.