btu output for these old Weather Twin and Wenig Convectors?

D107

These combo heating/ac units are from the 60s and connected to a 1956 monoflo system. There are three of the Wenigs and one Weather Twin. all other emitters are convector boxes except baseboard in porch.

Wenig: rating says '9K btu/hr' but not sure if that's an AC or heat rating. Model A9, 1320 watts. Box is 68L(or 60) 26"H and 8" deep. Actual element is 40"L, 8"D, maybe 2"? high. Fins are about ten to an inch. Intake vents on box are at least 10" high.

Weather Twin (green)probably from the '70s: Box is 45L, 28H, 10D. Element is 28L, 6D and descends at 45deg angle from back wall forward. Fins about ten to an inch. Assuming 2in element height.

looking for heat output on these. AND would they work with a mod/con boiler? Is this somewhat like hydro-air?

Thanks,

David