Thanks for the advice, I really appreciate it. But, something that might be of interest to everybody is the following;
Paul Steinberg suggested Julian McDermott Company of Ridgewood, NY. I called and was very pleasantly surprised. After speaking to a receptionist, I was turned over to Vernon. I told him that I need a flasher for my 1968 Superior Pontiac ambulance, to which he replied "Oh, you need a TG-12-90, we have it!" I asked him if it would be the same as the one I have and he said yes. He went on to tell me that they have been in business for seventy five years and he said that they make emergency LED lights, marine lights, light bars, etc. It was very interesting to speak with Vernon, he seems to have lots of knowledge about these items and he has many pieces of information. I was thoroughly impressed.
Thanks to Paul for his recommendation. I will try to attach a file of a page from McDermott's website showing my flasher.