Just yesterday I encountered the front-rear, left-right conundrum when replacing the clutch on my 71 911. I spotted a torn shift linkage boot that, although very well stocked, my mobile mechanic did not have in his workshop on wheels. After a phone call to the local dealer's parts department that including a lengthy discussion over front vs. rear, they convinced me they completely understood directional orientation and indeed had the boot I needed. Against the mechanic's better judgment I took my wife's trusty Bob Jackson mixte (hanging closest to the garage door) off its peg, mounted it from the left, non-drive side and beat over the hill to the P-car store. Forty minutes and a big mental sigh later I was pointing out to the parts "team" that front was rear and rear was front and would they please order the boot I needed as the one they were foisting was not it. Ah well, the unexpected ride was great, the weather spectacular and it only cost me an hour's mechanic time.
Terry McClintock San Anselmo, CA - just over a hill or two from Sonnen Porsche