Modern Molded Move-In Matchbox Monday Accessory Pack No. 3 Lock-Up Garage With Box 1958-59

I posted one of these a ways back but it had no doors or box. This one has what is called the B1 box which is an early box style. The Accessory Pack Series started in 1956 with the A box. This model first appeared in 1958 so I am thinking with this early box I am thinking it is from 1958.
Now as seen in photo #3 two of these can be joined together but it requires a pin that I do not have.
These Accessory Packs are hard to find. So far I think I have six with sets but there is a triple and a double so I only have three different sets.