The original Hall tips, which I have, are Stainless. So if yours are stainless I doubt that a chrome one would match. There's also a possibility that the tip angle would not be the same. Also, I attached mine with a few dabs of silicone sealer.... NOT. So I thought this am from memory.
I just went down and checked (one tip was off the muffler). I silicon glued 3 spacers on both the front and back ends an inch or so short of the end. The spacers (about 1" x 3/4") were some heavy fiberglass weave I must have had laying around. It was somewhat compressible so made a snug fit as I slid it on. On the outside end I put a silicon bead all the way around to fill the gap and keep it from possibly slipping. I did nothing to the inside end but you could certainly seal that easily if the muffler is off the car but you might want to leave a small vent. This has worked fine for 40 or so years!
My guess is that you could use almost anything as a spacer that is good to 600 deg or better (the temp rating of the silicon). So wood would work. Also there is a high temp JB Weld putty that could work "Able to withstand 450 degrees continuously and up to 500 degrees intermittently" which probably means that it still has strength at those temps and probably is good to well over 600. https://www.summitracing.com/parts/umi-8297
Richard To ski or not to ski, that is the question!