4A0 511 247B vs. 249

[n-engelbert at terrans.net]

I've developed a clunk on the rear driver's side of my 200q20v avant that
has lately gotten worse.  I checked the usual suspects, rear tie rods,
etc. but came up with the bushing toward the front of the trapezoidal arm,
or lack thereof on my car, it's worn itself right away.

When looking the part up in the family album, MG 5, SG 05, Illustration
45-00, the bushing inside 18A is what I need.  However, two parts are
listed for fitting 4A0 511 329A.  These are 4A0 511 247B and 4A0 511 249. 
The difference listed to the right for those is "8 teeth" for the second
one.  What does the "8 teeth" signify, and what is the difference between
these two parts?  The local dealer quoted me the same price for both, but
I'd really like to only order one.

Thanks!

Nathan Engelbert
83 UrQ DA900453
89 90q
91 200q20v avant