I have begun work on the Dragon FH 18 150mm Howitzer kit with the intention of depicting a weapon used in May-June 1940. The problem is I am starting to think that the kit actually depicts a very late variant.
After comparing the kit to photos of the real gun taken in 1940 and pics I found on the net of surviving weapons I have noticed a couple of things that concern me.
First off the barrel. On the kit provided barrel and the two after market barrels I have there is a raised area which I suppose represents a retaining band.

But on most pictures of the FH 18 show the barrel looking like this.

Am I right in assuming that the band was not seen on a 1940 vintage weapon?
The second question I have concerns the tyres. The Dragon kit depicts tyres with simple grooves. But the one photo I could find and some newsreel footage from 1940 shows a totally different design. It appears Trumpeter have attempted to depict this second pattern but rather poorly.

So basically, will I have to alter the tyres to the pictured pattern or is the simple grooved pattern as seen on the Dragon kit also applicable for a 1940 vintage gun?
Thanks for any help.
Cheers,
TimTam27