? about ebay replacement key

[zz2h33]

I'm fixen on buying an ebay replacement key for a spare since I only got one key from the dealer when I bought the car. I know I have to take it to the dealer to get it programmed/cut, but its still cheaper to buy it on ebay ($28) and take it in. Question is, the auction states "315 MHz, 4D0.837.231.F," and to make sure this matches. Well, it doesnt and I went thru all the dozen or so auctions for replacement keys and none of them match. My fob says "315 MHz, 8Z0.837.231.B"

Will it work? I'm thinking all the numbers dont have to match.

[zz2h33]

well i called one of the places selling these keys and they say the last set of numbers must match "231.F" and "231.B" are not compatible. He also said the 231.B keys are more rare so the price is $40.