Hello Mark,
This is a wonderful Ideal.
It is likely a 6RE/E model.
R means "renforce" i.e. reinforced.
The first "E" is ejector, and the second is Excelsior, i.e a high grade. This is demonstrated by the MDF stamp, meaning that a Director personally checked the gun.
S would mean rifled barrel that this gun does not have.
The wood is way above average...
Congratulations again, I'd love to have one like this.
WC-