A good friend of mine wants to sell/trade a Colt 1911 Government Mark IV Series 70 with original Colt grips, original Colt magazine, and a USGI holster. It was purchased new by his stepdad in 1973, as best as he can remember. It's been used and holstered, but bluing appears to be in "good" shape. Thus is not a piece that will be put under glass, but not a rusty paperweight either. I'm guessing 85% +\- overall condition, but I'm not an appraiser either. Any idea what it's worth? Auctions seem to be all over the board on these.