I agree with H. The plugs look good. I don't see any lean coloring.
Rough idle at a cold start with a carb'd engine is not uncommon.
A cold start rough idle, that goes away immediately at warm up, is almost always caused by the air fuel mixture.
Ambient air temperature and air density - Relative Humidity and Elevation (barometric pressure) can also significantly affect AFR.
Why does the carb NOT have a choke or an AAP? 
Gnarls. 
The carb does have a choke and AAP. Both work too. The BVSV that controls both, has a broken nipple on top. I glued a metal tube in so I can connect a hose to hopefully make it work.
45° this morning, started up no issues.
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