The PRONI guide to RC church records suggests that there are no records for the missing years. They are probably lost rather than illegible or fragile. I have noticed that the illegible ones were still sometimes filmed even though there seems little point. They did also usually manage to film the fragile ones (on the basis they won’t be disturbed again). This is what PRONI says exists:
Upper Creggan (Crossmaglen) (Armagh diocese) Baptisms and marriages, 1796-1803, 1812-29 and 1845-81.
It’s possible that a few loose pages from the missing period were found but I doubt the whole volume exists. The parish should hold the originals. You could contact the parish office to see what they can tell you.