which rear main seal is the right one?

[phlegm]

so Oreilys website says both of these will work but I cant figure out which one is best for me. Already looked at the oil pan gasket and it appears I ordered the wrong one from summit. Should have stuck with a local parts house on all this as they are easy enough to find, but it was May so I was staying home more and ordering in. Which one of these is the best one for an old SBC in my 71?

https://www.oreillyauto.com/detail/b...ain+seal&pos=4

This one says offset double lip and says improved design. not sure waht that means.

https://www.oreillyauto.com/detail/b...ain+seal&pos=3

This one comes with the little glide tab