I've seen stripped frames sell same day, multiple times, for $150 -$175, and occasionally sometimes lower.
LPK's in Canada are $200 I believe (and those are the Lone Wolf ones (with pretty poor reviews online), not even the OEM Glock ones).
So maybe it's reasonable to price it around $300, see if it sells in a week or two, then start lowering the price until it sells.
Don't be one of those guys who keep bumping their WTS ads for 6+ months because you have something priced too high and are not willing to come to terms with their fair market value.