You can't really tell by looking at how the Rams' TEs have produced under McVay but you can look at McVay's previous offenses and see that he does know how to use them.
Here's some numbers from his time as Washington's OC:
2014 Reed, 50 catches, Paul 39 catches (89 catches for Was' top 2 TEs)
2015 Reed, 87 catches
2016 Reed 66 catches, Davis 44 catches (110 catches for Was' top 2 TEs)
Back to the Rams: Higbee and Everett combined for 41 catches in 2017 and 57 catches in 2018.
So why did Washington's TE's catch so many more passes than the Rams TE's? IMO there are a couple reasons:
1.) Washington's TEs were more fully developed. I wanted to say they were better, but I don't think either of the Rams TEs have hit their peak yet. (Maybe Was' TEs were better but I still think the Higbee and Everett both still have some growth potential.)
2.) McVay has better options with the Rams. When Gurley, Woods, Cooks, and Kupp are on the field the Rams TEs are the 5th option, even with Brown, CJ, and Reynolds instead of Gurley/Kupp. It makes sense to integrate the TEs in the offense - and I think McVay has done that more and more over his 2 years here - but I am happy that McVay doesn't take more targets away from their best receivers just to boost the stats of the TEs.
AlbaNY_Ram