There are hundreds of these threads, do a search. This topic comes up almost daily - in my eyes one cannot specialize as a theoretical physicist at undergraduate level. The basics are the same for theory and experimental physics. You will study the same thing.
At post-graduate level, it involves different approaches to the same topics. This is when it matters. Either way, you'll learn valuable skills that have applications in the workplace.
And, re: your question about needing experimental skills in the workplace - no. Experimental physics isn't what any undergraduates seem to think it is. It's about using real-world data. Very rarely do experimental physicists sit in a lab building experiments - it doesn't really happen that way any more. At undergraduate, it's all the same thing really - in a 'theoretical course' you'll do more maths , the difference just about ends there.