Never heard or read of this cannon pack for the Hs 123
Only 2 x 7,92mm MG 17, 4 x 50kg SC 50 and 1 x 250kg SC 250.
Later at the Eastern Front two 20mm underwing MG FF could be applied through field conversions.
Btw, at the very moment I´m busy with polishing up the SAW Hs 123.
After finishing that I could apply LG 2 Dunkirk markings (interestingly still the pre-war RLM 61/62/63/65 combination)

The Wikipedia page, and the Luftwaffe Research Group page mention the canon pack, but it is referred to as "an innovation in the field". Looking back through my emailsI see that Flyright actually had a version of this Hs123 model flying with twin canons ten years ago. But I suspect this was an Eastern Front thing and not available in 1940.

Fran - would very much appreciate polished up Hs123 with LG2 skin for Dunkirk.