Quick help needed battery group #

[tomnan24]

I am having a battery replaced in my 2008 M35X this afternoon. A mechanic says he'll replace it with a group 24F. I saw some postings while doing a search and saw that it should be 34R(reverse polarity). Are these interchangeable? Any problems? Thanks.

[tomnan24]

In case it helps anyone else I bought the battery(24F). It was a Durolast Gold(made by Johnson Controls), the same battery that Autozone sells. It was listed as being 1" higher than the 34R which would have been a problem, but it was the same height and fit perfectly. It has 750 cold cranking amps, 935 cranking amps and 130 minutes reserve capacity. It has a 3 year replacement warranty with 2 years proration after that. It only cost $99, about $50 less than Autozone. My mechanic always takes care of my family and does excellent work here in the Canton Oh area.