Date codes on Goodyear Tire

What is the date of manufacturing on this tire and rim please. The tire is a Goodyear Polyglas E-70-14 with a DOT molded number of: MDLB. Y4A415.
The rim has M5 (with 9 below), then an 8, all to the left of the valve stem. On the right of the valve stem is the number 20 and then the Chrysler logo.

My Galen book doesn't cover some of the '69 wheels for "A" bodies. Here is a shot of the tire molding number.

Nobody? Gee did I stump the guru's? Come on guys, surely somebody can help. LOL

M5/9 8 -o- 20
M = Motor Wheel Corp.
5 = plant #5 (in CANADA) anyone what city/province?
9 = 1969
8 = August
20 = day of month (Wednesday 8/20/69)

MDLB Y4A415
MD = plant - Goodyear Tire Plant Gadsden, AL
LB = size - E70-14
Y4A = type - fiberglass belted w/RWL "GOODYEAR POLYGLAS E70-14"
415 = date - 41st week of 1975

& the wheel appears to be: part # 2660312 (4" bolt circle, 14x4.5")

Thanks!

So, this is not correct and "out of date" for a 1969 Dart?

NO, the wheel would be for a '70 model year vehicle
& the RWL were not used until the '70 model year
& any a-body with the E70-14s would have 14x5.5" wheels