R-Type EEPROM windows -- no stickers?

[shmupsrocks]

I'm trying to figure out how R-Type PCBs were shipped from the factory as far as the windows on the EEPROMs. Most of the photos I've seen have no sticker on the windows at all but I've also seen them with white stickers, black stickers, and cream-colored fabric patches. Any idea?

[shmupsrocks]

Any thoughts on this? Could they have been shipped without stickers? The vast majority of PCB photos I've seen have no stickers.