That's very interesting. I never heard or saw that bulletin before but I knew of that change and I mention it on my Henry J website. Now here's something interesting - my dad bought a new Henry J, serial number K5144-002510, in Souix Falls, SD on Oct 30, 1950 (I still have all the paperwork for it) and it had the open steering column as described before the change to the diecast moulding. About 10 years ago, I found an early aloha green Henry J in a salvage yard in New London, MN and it was serial number K5144-002512, just two cars later, and it had the moulding. The one my dad bought also had a 1947/48 KF Air Conditioner (heater) in it - probably dealer installed as the car was driven from Willow Run, MI to Souix Falls, SD for delivery.
Of course the one in the salvage yard could've been upgraded by a restorer at one time as it did have the factory Henry J type heater, extra bumper gaurds and a homemade continental kit.