Ok, this is confusing. According to the site mentioned above, Canadian copies of the Add Some/Susie single, which from appearances don't look like DJ copies, indicate mono from the lack of the S on the catalog code. (I did have a white label copy, now that I recall). Then there's a Canadian Slip On Through/This Whole World which also does not have the S.
However, the U.S. part of the site claims that Slip On Through/This Whole World does not exist on Reprise (
).
Things get even more confusing with the Add Some/Susie U.S. single. A copy with the Reprise and Warner-7 Arts logo (which is not a white label copy) does not have the S and misspells Al Jardine's name as Jardino. A subsequent issue without the 7 Arts logo does have the S, and still says Jardino. A third variation has the S and spells Al's name correctly.
Side question: Is there a stereo version of the alternate car noise placement mix of Susie Cincinnati besides the Made in California version?
I also mentioned above that the Canadian commercial copy of Marcella does not have the stereo S, but a mono/stereo promo does have the S on one side and not the other. The U.S. apparently commercial Marcella single also does not have the S on the A-side, but does have it for Hold On Dear Brother. (I mistakenly mentioned Cuddle Up as the B-side.) The You Need A Mess of Help/Cuddle Up single has the S for both sides.
Going further, the Child of Winter U.S. single has the S for the A-side, but not for Susie, which I previously heard was the mono mix.
Maybe this whole S stereo thing is a misprint on some singles.
Here is the U.S. part of the website's page.\
http://www.beachboys45.nl/USA-Regular-Reprise.htm