$4K-$5k is my guess -
(It is what I would pay.)
If you GB it, someone may come out of the woodwork or desperately wants it, and it may go higher.
Or I may be too high and you get no bids.
My MP40 kit sat until i dropped it to $3K - then it vanished.
MP44 no receiver went BIN for $4K in less than 24 hours.
An MP38 is rarer than the MP40 but difficult to gauge it's desirability against an MP44 - it is rarer, but with firearms that is not often a direct indicator of value.
I am thinking (based on bid watching on GB) it is quite a small number of people who are bidding for these items right now - not out of the double digits for sure, and maybe even less than 20.
I cannot offer you an exact figure only a guess based on items that are not an MP38 - lol.
I am not selling any more of my kits, I think the price rise over the last five years are an indicator of where they are going.