Back in 1985 the Spanish Army bought some new models from Boeing, since all "D" production line was going to the US Army they sold the Boeing Vertol 414, which was the civil version half way between the Super C and D.
Those 414 had the L-712 engines on them, FRB's and RPM's indicators in %'s, although oil cooling system and AGB's were the same as in C models.
The other day I was invited to go to my former Chinook batallion brand new Delta simulator. The cockpit and instruments all looked quite alike a C model. Although I haven't seen the BV 234 I would think that they would be closer to the BV 414 than to a D model.
Just my 2 cents.
Buen Vuelo