I agree 100% that opening the sump plate is good practice. I opened mine in May to do my every-other-race-weekend oil change and all was good. Recently opened the sump, simply because my Autospeed aftermarket sump drain was seized/wrench hole is partly stripped. I found the oil pump screen & baffle plate was separated.
So I removed the screen and planned to replace it with a new used one from a generous Pelican (thanks Dave (dtw)) upon receipt of it. Since the earlier cars ran without this sump screen, which I believe was introduced in '82, I ran the car without it.
Well I think the screen shed some pieces upon separating itself from the case flange. So there went my engine....... Oil temps shot up shortly after putting an at-speed load on it during lap 2 of qualifying session. Oil pressure warning light illuminated solidly upon throttle lift and engine power went kaput.... Will have to tear it down and see what caused the failure. Doesn't sound bad mechanically or audibly. No knocking sounds or funky exhaust note.