For the latest spring LMA desgin, there are two different spec.
It's the overall length difference and easily can tell by the presence of bottom spacer (-305) or without (-003).

The LMA pocket geometry on the cyl head is different between pre-00 and 00+ models.

00+ model (both the MT and AT) left the factory with the latest LMA without the bottom spacer (-003) because the cyl head was machined that way.

For pre-00 models, there used to be lots and lots of different spec/design LMAs, like 7 of them and even there was a difference between MT and AT.

Initially, Honda made mistake in superseding all LMA parts no. (including the pre-00 models) into just one 00+ spec of -003 that has no spacer at the bottom.
This made the LMA length/height shorter causing extra mechanical noise if used on the pre-00 models.

It stayed like that for several years but finally, Honda acknowledged it and released new LMA for pre-00 models with the spacer at the bottom (-305).

Don't know whether the spring rate is the same or not between -305 and -003.
Extra info here; http://www.nsxcb.co.uk/showthread.ph...8602#post68602

For the clarification, 00+ AT model is C30A but left the factory with -003 so can't use -305.

Kaz