As far as I know the only R/T models that come with limited slip are the ones with manual transmissions so if all the ones you looked at were automatics then yes.

 

I believe they were all A8 models, so this makes sense. I thought they began using the LSD in all R/T and up models since 2017.

 

I believe, since 2015, LSD is an option for R/T models with automatic trans that could be ordered during a build. LSD swaps are available as after market online, or OEM through dealerships.

 

I drove a several LSD equipped Challenger's over the last week. To be honest, I think I prefer the conventional unit. Cornering feels better, and it's quiet. If I were living in a snow state, I think a LSD would be a must-have. If I get into a pinch with sand, I'm sure traction control will do a fine job of getting me out.

 

lsd was not a option on 2015 up to 2018 on the 5.7 rt with a a8 tranny , but they are now you just have to order or check the right package option

 

I did some research through Dodge Customer Care and the LSD was indeed introduced into the line up as an option for the Challenger as well as being introduced at that time with the R/T Scat Pack. It could be ordered during build for the R/T with auto-trans.