You absolutely should get a new manifold, hose and adapter set for your 134 system.
There are indeed adapters and such available to switch back and forth, but the cross contamination risk is too great. When I bought my 134 set in the early nineties I had to pay big bucks for it. Now, however, a good set can be had for under $100.
Don't be penny wise and pound foolish, buy a 134 set. You will make use of it for the rest of your life.