Does anybody know off the top of their head how different front and
rear Boge springs are?

Front, part no. 251 411 105 952A
Rear, part no. 251 511 105 952

The reason I'm asking is because the van doesn't appear to be sitting
as level as I'd expect, and I'm wondering whether or not its possible
that my mechanic installed them incorrectly.  I never took them out
of the box so I don't know if they're visually different.

Thanks again
Jeff