No, there is no difference between RGTU and RGPV.
RGPV stands for Rajiv Gandhi Proudyogiki Vishwavidyalaya. Almost all the private engineering colleges in the state of Madhya Pradesh are affiliated to this technical university.
RGTU stands for Rajiv Gandhi Technical University which is simply the English translation for RGPV.
There is however one college about which students get confused a lot. It is UIT or University Institute of Technology. It is an autonomous govt engineering college located inside the premises of the RGPV campus. The syllabus for UIT is the same as other RGPV colleges. The only difference is that their exams and results are announced by UIT itself.