Yeah, OK. It's probably the extra "oomph" of those bells and gongs that help push you over the edge. When they're inaudible, the end of the "Resurrection" symphony can actually sound pretty static. Again, this may seem like a point that only a Mahler-lover could care about, but it obviously meant a lot to Mahler himself, since he took the trouble to have his own set of bells casted (cast?) for the work.
My guess is that gongs (tam-tams) probably left something for the imagination in those days, but I'll bet that Mahler made certain that they got struck plenty hard. Remember, it was a common trick to end dramatic opera acts with a big gong roll in those days. Few conductors would resort to such "cheap theatrics" these days.
Barry