1974 - Optimus 45K New in box

I picked this up on craigslist. It is a new in box 45K. Anybody know the age of this?

 

I'm guessing 70/80's - 60's at earliest. Check the flap of the box for a date code.

 

Would this be the date code?

 

It's my opion that such stamps found on Optimus boxes from the 60's onwards denote the year in the last 2 digits - making that 1974.

 

Thanks

 

Here are some pictures of it put together. What would the longer extra stem be for?

 

The other stem or riser goes on the stove for use with sea swing . Do a search for that and you will see what that is. Just a swing the allows the stove to used on a boat/ship.

Cheers!
Jeff