Differences in old/new P220ST frame styles.

[Kipling79]

I have just personally discovered that older P220ST's have frames leftover from the P220 Sport production.

I was hoping this might mean that my frame was built to higher tolerances, but I am also a little worried that this older frame might coincide with older slides which sometimes have the extractor problems I have been hearing about.

Aside from having different types of rails, are there any important differences?

Thanks