Yes, those epoxy filled coils do split the outer jackets from excessive heat that the epoxy does not let transfer out of the coil. The me4sh is the final cover before the outer jacket. One other thing to test in the coils packs is the resistance of each spark plug cap. Higher resistance is bad, will also help cause higher coil core temps, and help to fail the coils. To test, unscrew the cap off the wire, test with ohms meter, on Rx1k scale, should be no more than 5K ohms. Look on the cap, there might be a number on the body, like LB05F, 5.0 ohms would be the resistance value to have.
Also, in addition to the jets and passages info already given, which is excellent, carb rubber manifold to head sealing is critical, best to use Three-Bond 1194 case sealer between manifolds and head.
Hope this helps.