As far as I know,Rockers were always 4 ply shells,so if that is true what you have there is
either the last version of the Ludwig Standards,offered in 1982,see this link,
http://www.vintagedrumguide.com/images/ludwig_sets/1982_ludwig_drumsets1.jpg
or the Ludwig S/L,shown in the 1984 catalogue,
http://www.vintagedrumguide.com/ludwig_drumsets_1984.html
Both series had the 6 ply BD,4 ply toms,both series were offered in black,and white cortex.One thing I noticed from the catalogue pic/ scan is that the Standards are showing no badges on the toms,I can't see the badge on the kick to well,but the badge on the Floor toms looks like a Blue and Olive badge,don't know if they came that way,or if Ludwig was in a hurry to get a pic of the line for the catalogue.
A couple other anomalies/differences I noticed,My S/L kit had beigey/yellowish interior paint, while a couple of these 6 ply bd 4 ply tom kits I have seen pics of had clear interiors,don't know where you are but as I remember the clear int kits were in Europe.
The other anomalies was the BD spurs,most had the 1303 straight spurs,like in the catalogue,but mine had the 3/4 thicker later curved /disappearing spurs,and I have seen a couple with the older thinner curved spurs.If your BD is 6 ply that would be the first I have seen with the Rocker type spurs and mounts.
By the way,my 4 ply toms were just under 1/4 thick,and my BD was right at 5/16.
I don't have any scans of a Ludwig 1985 Cat,but the 86 cat shows the rocker/standard
type lugs,and I am not sure but I thought the earliest rockers came with classic lugs,
and have heard that sometimes later versions were shipped with classics,or that some times someone would replace the rocker lugs with classics,both scenarios make sense to me because the hole spacing was the same.
So IMO if you have a 6 ply Bd I think you have an S/L kit if the BD spurs mount are original,or you could have an early rocker kit with a leftover 6 pl y BD ,you never know with Ludwig.
As far as pricing for sale,I think asking 500.00 is a good place to start,I think top dollar would be 450.00