Number system/date codes for GH2?-and flash question

Hi all

Some of you may have been reading about my Panny repair fiasco in the general topic forum. Won't go into details here, but by mistake, Panasonic sent me a both refurbished camera and my own camera, repaired. They want to refurb back, even though the asst. manager offered it to me because it was taking so long to repair my own camera. I will probably send it back (and may not have a choice), but I'm curious if anyone knows how to interpret the serial numbers as to date of manufacture.

My camera says WEIAA001134
The refurb says WEIJA001423

On my camera it appears they did not replace a little plate on the flash shoe that covers 4 screws holding it on. The refurb has this plate. I don't have a flash to test it, but I'm wondering if those screws should be covered as they might interfere with the flash in some way? ( Seems like they should at least send me that plate anyway- looks like I might be able to slide it in there....)

Thanks for any insights....