The two struts do have different numbers, don't know why.  I'll take a
gander at my 87 sitting in the driveway and let you know what's on mine,
but I THINK B was on the passenger side.  I'll let you know what I've
got in a little bit.  Mine were replaced by the dealer at the time I
bought it (1/95) as a condition of sale.  Thus, they are the VW parts. 
Meanwhile, there were others that suggested aftermarkets were better a
while back and suggested the stronger strut on both sides.  The archives
(if and when they are available) may give you more info.  The postings
that I'm referring to were about a month or so ago.

I'll let you know later about my part numbers.

Tonya
87 Vanagon GL Wolfs
74 S. Beetle