+1. I recall programs that informed me I would not receive credit for anything, most things, and any anything in-between.
My program reviews its handful of master's students on a case-by-case basis after admission for both course and thesis credit (and I was not notified of this until after I was accepted).
Course credit must be approved by the current instructor of the course, who may not even be in the clinical dept. Even then, there are some courses that the program refuses to transfer (usually the clinical courses), even if they were taken previously because they want to verify that you have the same knowledge base. Most of the time, no one saves any significant amount of time with transfer credit, although one might be able to transfer a few stats classes and core electives from the other depts (e.g., social, bio, developmental, etc.). Of course, some of the instructors of those electives believe that their electives are worth retaking and refuse to give you credit, so then you're stuck taking the same stuff again anyway.
Thesis credit varies widely as well, with mostly the clinical master's students receiving credit (although even that varies dependent upon the thesis and the students' advisors). However, even if the program doesn't give you "full" credit for your thesis, as long as you have completed one, and they find it acceptable, you are only required to complete something along the lines of a master's equivalency project rather than another full-blown master's thesis... so just run out another research project and be done with it (which sounds simple enough but can turn into a living nightmare, dependent upon the project... and in the end, you're completing all/most of the same requirements as everyone else in the program anyway, without the add'l master's degree).
Due to the designed timeline of our program, the most time anyone in our program is allegedly able to "save" by having a master's degree is ONE year (although most of them are unable to do it). And, with the way that our program is starting to push the traditional (non-master's) students, even they could complete it in the same timeframe as the master's students if they really pushed themselves.
Again, this is for ONE program. It really does vary, so you would need to ask programs what their policies are for course/thesis credits during the interview process. However, I'm not sure I would really focus on this too much personally. I made it a point during my interviews to emphasize that I would be willing to re-take anything needed because there were programs that I knew of that were hesitant/unwilling to take students with master's degrees. I wanted to do whatever I needed to improve my chances and to decrease their thoughts that I was simply trying to take a short-cut through their program.