Eljer/ Valley 2nd gen single handle tub new cartridge VP-1964 missing o-ring?

[Mike Rock]

Hello, I have a 2nd gen Valley/ Eljer tub faucet. I ordered part Valley VP-1964 BG ( same as Danco VA-4). According to the plumbingsupply.com website , this will fit my faucet. But when I received it, I noticed that it is missing an O-ring, see pics below from plumbingsupply.com website, and it seems when I do a search, I see some other VP1964 cartridges missing it also, while most others have both. Is there a reason for this?
I have not tried it yet , this is for my tenants apartment about an hour drive for me,

 

[Mike Rock]

So just to update, plumbingsupply.com got back to me and said they sold hundreds of these with no complaints or returns. And this part is several years old that they have been offering.
They said it does look kind of misleading with the 2nd indentation missing an O-ring, but no reason for concerns.
I will update when I get it installed in my tenants apartment.