What OSS said. No harm in doing a compression test for fun other than it makes you start wondering if you should rebuild or swap. Had you not done the first test you would have likely driven around in blissful ignorance of the engine's impending doom - in another 200k miles. If the intake was open (air cleaner off, carb open to rain) when it was stored outside then Dallas Cruiser very well could be right - some rust on a cylinder wall and/or rings. This could lead to poor compression, increased blowby, burning oil, possibly even a plug fouling occasionally. It could also lead to nothing. I'd take the chance at this point and button it up and go. If it turns I'm wrong, which has been know to happen, and the worst case happens (engine needs a rebuild) you've only lost a day or two of work on what'll be a month plus project.
Of course, if you're looking for justification for an LS swap ("Look Honey, everyone on the forum said the engine's toast. I'll be money ahead to put a V8 in it.") then yeah, pull that boat anchor and start looking for a donor.
Of course, if you're looking for justification for an LS swap ("Look Honey, everyone on the forum said the engine's toast. I'll be money ahead to put a V8 in it.") then yeah, pull that boat anchor and start looking for a donor.