Sounds about right. Might get a little more if parted out though. But you have to figure in new bore and piston plus shipping then a new crank and time and labor costs.. Part out might be best if trying to make $.. just my .02 though..
Then like Awk said,,, these cyls don't have many bores in them. If there is a big gouge/score in cyl wall it could be over for that cyl.. Tell that to the seller and see if you can knock the price down or even ask if you can pull the top end off quick before forking over any $. Otherwise its a stock blasty needing a complete rebuild +.. If newer year with hydros than you should be good, if not than ??
You got to protect your investment.