I'm going to guess that it's 23.976 fps, which is not the same as 24fps. Unfortunately, some people like to "shorthand" the terminology by rounding up. Now, there is a valid term of "24p" which refers to a "progressive" frame rate, but that IS 23.976. In any event, you have to find out for certain. The editor is your best bet for that information. But you can also check yourself...
Open the movie in QTPro. Hit CMD-i (info) and look at the listed frame rate. I'd be extremely surprised if it's 24. That frame rate is, to the best of my knowledge, used exclusively for cel animation and actual film.
OK, that aside, and come to think of it, you could save yourself some trouble by not changing a thing and referring exclusively to the movie's timecode burn and not worrying about Logic's timecode counter at all. This will produce a perfectly in-sync result. For example, if your music starts at 01:02:03:04 with respect to the picture's t/c burn, go with that. I would suggest you to use the following routine for printing each cue:
1) set the playhead at the start frame of the cue. Do not worry about whether the playhead is positioned on a musical beat. We're out of musical territory right now. Go for the first frame of picture as to where your cue starts, using picture's t/c burn as the reference.
2) in Logic's transport, click/hold on the bits value in the SMPTE display and scroll it down in value until you just see the PREVIOUS frame of picture come into view (that would be frame 03 per the example timecode I gave you above). Then slowly scroll the bits value upward until you arrive at the actual start frame of your cue (here, frame 04). Set your left locator (without rounding) to that position (the key command for setting left locator without rounding is useful here). Then set the right locator to a bit past the point of the end of the cue. At no point during this process should you be concerned with whether Logic's t/c counter matches picture's.
(BTW, that little bit of necessary bit-scrolling evil is to ensure that your music cue starts on the "leading edge" of that frame of picture).
3) Bounce your cue, naming it similar to this:
"1m1 Final +01_02_03_04.aif"
Because of the timecode discrepancy you're experiencing I suggest you bounce an AIF and not a WAV. I can explain that later if you want.
To answer your last question, what constitutes "standard practice" depends on who you ask. When I print cues I take the most conservative (i.e., foolproof) approach there is: to pop my music files with a 2-pop at the head. However, for your purposes, you won't need to do this. The procedure I outlined above is fine.