Slop, as in loose/sloppy.
Is the shifter firm or does it move around easily when in gear?
Yes, put in reverse and wiggle the shifter. Maybe try pushing it slightly toward the dash, see if that activates the lights. If it is bushings, they are inexpensive, something in the order of 80 cents or so, you'll need two.
I can't say what the difficulty level is yet. Everything I read said it was fairly simply, a matter of disconnecting the shift linkage from the tranny and shift lever, replacing bushing and reinstalling. I just ordered a set of bushings for the 280SEL, and will install them soon. A floor mounted shifter should be somewhat easier than a column shift.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.