At under $8, you can assume that it is group III oil, not synthetic. If you are going to go group III, might as well save your $ and get Rotella.
Why do you keep calling Group III oil NOT synthetic? Synthetic is a marketing term -- it doesn't mean anything. Grp III+ (RTS T6) oil has all the properties of PAO (GrpIV) and Ester (Grp V) All synthetic oils contain some amount of all three types, it is just how much of each in in the "synthetic" oil in question.
For instance -- Redline is predominately Grp V but also contain some PAO and Grp III too.
Amsoil is predominately Grp IV (PAO) but also contains some Grp III and Ester. It all depends on the blender. Why do you keep bringing this up? Each company determines the optimum combination of synthetic basestocks to meet their specifications -- END OF STORY !!
BTW, Rotella T6 is an isomerized slack wax Group III+ oil which is NOT your garden-variety Grp III synthetic oil, it is equivalent to any "synthetic" oil on the market and is sold in Europe as Shell Helix and is the Ferrari factory fill oil. If it is good enough for Ferrari engines, I think it can run in any engine up to and including Formula One engines.....