64-67 arm rest bases are now reproduced. Also looks like a better quality arm rest pad is also now made. Check it out: https://oldbuickparts.com/product/1964-1967-buick-front-arm-rest-chrome-base-14/
CARS has both the pads and the bases. They are beautiful! https://oldbuickparts.com/product/1964-1967-buick-front-arm-rest-chrome-base-14/