Well last summer I remember a few 752s that were in for long period of time, including AK, AG and AE but id assume this is more so down to the smaller size of the 752 fleet and there is no need to shuffle them around unless it is for maintenance which tends to be done by swapping the return aircraft at TFS - the 752s don't have any night duties like the 733s.
Overall airlines allocate bases aircraft types, such as 2x 752 3x 733 and not registrations.