No idea. Try calling or emailing Ann Marie Cross. She will get you a straight answer.
If I remember correctly, Tower has been in and out of stock with these many times over the years, so I am not particularly worried. Besides, there are many places around the planet that stock the 91. Point and click and give them your credit card. I order stuff from Japan, Germany, whatever. If there is no U.S. distribution, you can bet that there will be heavy competition from distributors in Japan and Singapore and such that will want your business.