Milano/75 castor bushes

[Jonathan Coates <cdico.demon.co.uk@cdico.demon.co.uk>]

I bought new castor bushes, if that's what they're called (the rubber
washery things which fit either side of the body near the headlights)
from the dealer as mine look buggered. When he gave me them they looked
like 4 identical bits, but when I looked at the invoice they were listed
as 2 of part No. X and 2 of part No. Y. How do they differ? How can I
tell which is which? And which bit goes where?
Any help appreciated, TVMIA
-- 
Jonathan Coates
164LV6 Daily driver
752.0TS T car
Alfetta 2.0 GTV Veni Vidi Visa