All of the old metal Gillette dispensers are really easy to open up. Just be careful about bending the sides as you do it.
The only thing is, I doubt it work very well if the blades have glue spots on them. The blades that originally came in those dispensers had a very light coating of oil that allowed them to slide out easily. You may find it's more trouble than it's worth even if you use blades that don't have the glue spots.
“Trying to be happy by accumulating possessions is like trying to satisfy hunger by taping sandwiches all over your body.” -George Carlin
My Collection: http://rtccom.net/~sledge/Razors