Not really, no, that'd be a waste of an awful lot of storage space/bandwidth: new snapshots automatically replace the previous ones.
The sources are tracked in a VCS, but the build scripts aren't really designed to build a pinned revision.
TL;DR: No

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MRPI being broken is only the tip of the iceberg, so even with a previous MRPI version, you probably don't want to be running the current revisions of almost everything, because the issue lies in a dependency used by quite a lot of stuff.
I do test them locally before pushing them, but due to an unfortunate series of different issues, I caught one issue with the original local test builds, then tested the fix in a manner that bypassed MRPI on Kindle, and double-checked on Kobo, where the issue is not as obvious, but a different one was, and that one required pushing new builds online to fix... and that in turn broke MRPI ;p.