I bought it used, but I called MusicMan to ask about the pre-amp controls and to get a birth date for my bass.
During that conversation I asked about the pickguard and the guy said that some of them had that pickguard.
It is possible he was uninformed and bullsh!tting but it could also be the truth.
Maybe the weird diamond plate material was out of stock for a bit and they went with simple cheap single ply black for one run.
We also talked about the introduction of the compensated nut that they started putting on them in year three I think, and he they did not have one he could sell me.
The compensated nut started in late 2005, at the same time they started using it for their standard models. Not sure when exactly 'though.
There are a few strange inconsistencies so who knows what they did and why exactly. Like how early ones in 2003 and very early 2004 had the pickup wired in series, and later in parallel. Ok, I haven't been able to see ALL of their basses in that period, but every single one I've been able to verify fitted the description. Incidentally, teh series wiring suits teh 2-band preamp better, in my opinion.
That's for the 4-string ones, 5-strings appeared to always be parallel... but I only verified 2 of those so I'm reluctant to bet my life on it 'though