First find out for sure the size of the speaker. They made both a 1x15 for the 200S and I believe a 1x18 as well for the 2000S. I think this is the 1x15 due to the space around the speaker and I've been looking for one of these for many years. They seldom come up as everyone wanted the 2x15 version. By the way the badge alone is worth about a hundred bucks to some people. I would pay that pricefor it (the cab) right now. Damn I want that cab for. My 200S. As that's what the bass player for the Kingsman (Louie Louie) was playing the first time I saw them in about 1964.
It's either that or a 155-S, hard to judge whether it's a 15" or 18" from the pic. Ca.'72 to '74-ish. The speaker's definitely original, I've owned many 1970's Sunns since 1975, that's what came in there...Eminence, they had the vented aluminum dust cap. The surround looks right to me based on memory, but it could've been reconed. The bad news is that those speakers SUCK and you'd want to swap it out anyway. The "M" stands for Magna, which were Sunn's premium speaker (actually OEM'd Cerwin Vegas) and those are decent speakers. The Eminence, though, are useless. The 15"s were only rated at 60 watts, can't remember what the 18" was supposed to handle.
The good news is that those '70s Sunn cabs are really great sounding bass cabs, that's what you'd be paying for.
It's a 1X18, either a 118M or 118V, probably a '72 118V or a '73-'75 118M. It's 30" x 30" (to match up with the 350B amplifier box), all of the 115's were 24" x 24"; pretty obvious to those familiar with the two because the 15" driver took up a
noticeably higher percentage of the baffle.
The "V" was Cerwin Vega loaded and the "M" had a "Sunn Magna" driver which was manufactured by the Hartzell speaker facility in western KY.
The "Sunn Transducer" drivers, as used in the 115S cabs could be CTS
or Eminence, but those were never available as OEM in the 118 cabs.
CTS and Eminence and the other speaker manufacturers in that corner of KY sourced their parts from the same manufacturers, much the way that auto manufacturers in Detroit source their parts (seats, airbags, control modules, etc.) from the same manufacturers, much like the RV industry in the Elkhart/South Bend IN area, and
many area specific industries do in the interest of capitalizing on the economy of scale afforded by supplier and/or experienced workforce logistics.
A speaker is far less complicated than an RV or automobile, so it's often difficult to tell a CTS from an Eminence from that era without the EIA code, the frames, dust covers, magnets, etc. are virtually identical/interchangeable. Also the line defining "who built what" with these products can be blurred by one or the other company actually contracting with their "competition" to manufacture high volume products.