If your Eb3 is "skilled worker" (Category "f" on From I-140), your I-485 should be filed to The USCIS Nebraska or Texas Service Centers, depending on the location of your employment. See Form I-140 instructions for addresses.
But if your EB3 is not "Skilled Worker", but "Professionals (with Bachelor's or above degree" or "Other Workers (Unskilled Workers), then you need to file your I-485 to the USCIS Dallas Lockbox (same as the EB2 filing address). So, check your I-140 to see what kind of your Eb3 is (Category "f" on I-140 or not).
