CVA's (that's the original CVA, not the current one) wood stocked sidelocks were generally good (not excellent) quality starter guns. A mint Hawken is valued at $335 in the Fifth Edition (2007) of the Blue Book of Modern Black Powder Arms on page 57. The value falls off rather quickly, however, to $175 at 80%. The primary consideration, of course, is the bore condition. 'Unfired' is not the same as 'mint' condition, so some reduction off the $335 value is reasonable; the book suggests $290 for a 98% condition gun.
The Hawken was discontinued by CVA in 1994. 'Unfired' CVA Hawkens are unusual finds; they could almost be considered rare. If the gun is truly unfired the 98% book valuation might be reasonable.
Blue Book prices are only a guide, of course. Prices can and do vary considerably. I suspect that the guns quoted above were not unfired or mint condition, so the prices would be expected to be lower, about the ranges mentioned (pawn shops and internet auctions don't generally deal in 10 year old guns in mint condition).
CVA guns generally bring lower prices than Thompson Center, their nearest competitor. They are reliable, good shooters and can be a good value. $300 is not a bargain price, even with the extras offered, but for a truly unfired condition gun it's not $150 overpriced either.
Without seeing the gun it's hard to say, but $225 might be a good price considering the extras.
I've been shooting both Goex and 777 for many years. I'm not aware of the need for a 'buffer', whatever that is, when using 777. It does have a higher ignition temperature and does not like to be tightly compressed, but if one takes the time to develop the load properly it will give performance equivalent to if not superior to Goex.
