[Roadsters] spark plugs

[Tim]

I have read that the BP6ES is recommended for my 1600. I went to get a (backup) set the other day and the guy at my local tried to to tell me that the "NGK 73333" --that he showed me on his screen-- was the same plug. I didn't believe him and said thanks any way as I have never seen "73333" mentioned as a comaprable plug. 

Does any one recognize this NGK number? And what stores have the BP6ES in stock? I got a set from NAPA once but the one closest to me is only open 3 hours a weekend and never when I need to go there during a weekend.

TIA

Tim