Links to HK year of manufacture code info and to recent internet sales on a large internet auction site that illustrate my previous statements.
If the moderators feel that the links to closed auctions are not allowed - please, feel free to remove the links and accept my apologies.
Going back 3 months on a major internet auction sales, it appears that the HK91 sales range from $2000 to $3500, with majority clustering in $2500-2700 range. One should also account for extras(mags, scopes, extra stocks, etc.) that were included in some and probably contributed to some of the higher priced sales, but were also part of some of the lower end and mid-range sales too.
Some of the HK91s in the links are in "fixed stock" configuration.
An original adjustable HK91 stock can be purchased separately for around $250-350 extra.
On the other hand, given the outstanding condition of this rifle, I would have to revise my previous retail price estimate to $2750.
It can sell for more or it can sell for less depending on who wants it and how badly they want it.
However, we only have the previous sales records to compare to and to make any kind of projections.
And these are just that: projections or estimates of price based average sales prices from the past 3 months.
Hope it helps to clarify my original statement.
Completed auction site numbers: