well as far as i know my front susp is stock minus radias arm bushing and a lower bj wich i replaced when i bought the car at 122k. The uca's are trw iirc but cant tell if there original.

the front is tight and not giving me any problems at 134k. Is it likely they were allready replaced?

Most likely they were cared for... are there grease fittings? if there is then definatly been replaced, if not then its a crap shoot if the previous owner/s replaced with OEM parts.

no fittings on the upa's..and only 1 on the lbj that i replaced.

if they lasted 135k and are still tight i can't imagine there originals.

as long as you have no play then I say leave them alone, just now would be a good time to pick up the OEM version of LCA's and I heard different for UCA's better to have the extra parts now then need them in a pinch later ;)