According to Wikipedia, the company shut down in late June, 2009
I think this is not legal to share it as this is not on public domain and there are still commercial rights on it even if it is currently commercially not available.
The question is a bit complicated because if Passalong was the seller it is not certain that they do have the copyright right over theses recordings as Crowfly (co-founded by Chuck Ainlay) was the society who produced the recordings and seems to be still running. So maybe we can hope to see them rereleased in the future, and this time lossless and DRM free. After all we had to wait 2009 to le able to legally get a copy of SGT Pepper MONO on CD.
But if on the contrary there are not plan to make these recording commercially available again we can assume that then it should not be a big deal that the MK fan share them for free between them (but not directly here of course).