Mine is folded up or I'd count for you to confirm. However, I'm under the impression the manual is an easy way. Here is page #2 of the WCS manual from ipdb.org:
The last two columns are "Playfield" and "Backbox" which (I believe) note if the bulbs are located on the playfield or in the backbox. I believe you can just count up the number listed for a total of:
14 x #906 Flasher
7 x #89 Flasher
You'd have to decide if you wanted to color match or go with warm/cool white. I think cool white would be fine (the domes are already colored) if you're unsure.