I know this is an old post but I just talked to one of my bearing suppliers and he claimed the 308SG was available. This is the link he gave me.

https://www.motionindustries.com/productDetail.jsp?sku=00056902

I note though that the width of this bearing is 23 MM or 0.9055" which differs from the two widths in this post, 0.795" or 0.825". Any insight on this? Thanks.

"We live in a time when intelligent people are being silenced so that stupid people won't be offended".