Josh,
Auto engine oil-filler caps have often had the word "OIL" in raised or stamped letters on the top. The old joke tells of some guy or gal who went into an auto parts store asking for a new "710" cap. After the parts sales clerk questioned him/her further he found out what they were looking for. The punch line is that the word "OIL" almost looks like "710" when it is upside down, so the ***** shopper thought he/she needed a "710" cap.
I just thought I would share the info on this joke with you, since I constantly feel stupid when younger guys are making jokes with modern internet slang and abbreviations. I seem to be the only guy that doesn't know them very well.