Video Pinball cart with "P" on end label but not PAL?

I noticed a section in the rarity guide for picture label variations and some state that they have a "P" on the end label even though they are NTSC. I noticed that Video Pinball with a "P" on the end label is not listed on the guide. I have picture proof that it exists and I tested it on both a 2600 and a 7800 system and it works perfectly.

Here is a link to the part of the rarity guide that shows some NTSC carts that do have a "P" on the end label but notice Video Pinball is not listed with the P:
Rarity Guide LINK

Is this a "rare" cartridge because I have never seen one with a "P" on it. Or, are these more common than I think? Who else owns one of these? Here is a pic of the cartridge: