That silver thing, as ChaosLord mentioned is your 256kb memory add-on. Leave that in there! lol
Re: batteries, some 3rd party internal RAM boards do have 'em. Doubtful you have this particular one, but the worst offender was the Rejuvenator board. So yes, when you crack open the case, might be worth looking into.
A1000 mobo's only came in a few different flavors IIRC. European ones didn't all have the Daughterboards (WCS for Kickstart) and the main differences between the two North American boards had to do with copper vs. tin PCB traces. Personally, I like the copper machine (revision 6) just because it's different and I believe Paula, Agnus and Denise were all ceramic/metal cased chips (unlike plastic which was used later on). Also, real early A1000's did not come with an EHB Denise. Looks like when Commodore received A1000's from trade-in programs or whatever, they'd stamp "refurbished" on the underside of the machine and outfit them with later revision Denise's.
Congrats on your machine! The A1000 has a couple of irritating factors going for it (lack of system changing pal<>ntsc standards, expensive to upgrade), but is a great looking little computer that'll run most anything you might want it to.
