While speaking with Coop after being laid up in the hospital by the motorcycle gang, Jim tells Coop the gang members are 'one percenters' (also expressed as "1%ers'). One percenters' are (usually) motorcycle club members who do not comply with the law, as opposed to the other 99% of the motorcycle riding population who do comply with the law.
When Coop reveals his shoulder tattoo, it's inked over a scar. When someone leaves an MC, their 'colours' - tattoo - is cut out.
After making two previous appearances, a voice-over gag at the start of "With the French Heel...", and having his name mentioned on "The Battle-Ax and the Exploding Cigar", this episode marks the final appearance of "Coop" (Bo Hopkins) and will never be mentioned again.
The driving scene with "Jim" and "Gail" required multiple takes as neither actor could remember their lines correctly (Laurie Jefferson's lines were very technical and you can see a couple of them had to be dubbed). This can be viewed online under "Rockford Files Gag Reel (revised)" on the popular video site.
Dennis Burkley ("Animal") also appeared with James Garner in Murphy's Romance (1985) as Freeman Coverly who, it is disclosed in the film, gave Murphy some blood when he needed it.