TZ is somewhat unique in that 8 of the GI sockets initially contained the now hard to find #545 (#24-8825) wedge base bulbs, these are special blinker bulbs that Coyote mentions above, used only in TZ, DH and NGG. Those 8 sockets are a different color so easy to identify. Most TZs around probably just have the regular #555 bulbs in those sockets because over the years the #545s were hard to find, and I suspect most operators just found it easier to replace those from their #555 stock. But its a really nice effect to have the blinking ones installed if you can get them.

Here's a video showing that feature:

I just did a search and see that Pinball Life seems to still carry the incandescent #545 bulbs, but I don't think they are produced any more.

http://www.pinballlife.com/index.php?p=product&id=3005

Years ago I installed a LED version made as a replacement, still available at Marco. They have worked really well.

http://www.marcospecialties.com/pinball-parts/05-545-WWB