I doubt it would/will be much of an issue. It's hard to imagine AA achieving an "end state" at LAX with longhaul 777/787 beyond LHR, GRU, TYO, ICN, PEK, PVG, HKG, SYD and AKL. Given the scheduling realities that such an operation would entail, it's likely that the natural departure and arrival banks for such routes would mean a "peak" of flights (and widebody-capable gates needed) around mid-day/1100-1400 (TYO, ICN, PEK, PVG, possibly HKG), another in the evening/1800-2100 (LHR, GRU) and finally one in the late evening/2100-2300 (SYD, AKL). As such, it seems unlikely that AA would ever need more than 3-5 widebody-gates at one time, and between what AA already has in T4 and what AA will soon have with expanded access to TBIT, that shouldn't be a problem.