Yepper, it must be old for several reasons. Screw Back for one. I never had one and dont remember afer 39 years what the "Pledges Pins" were like back then.
I think it kind of looks similar to one that Jono sent to IHQ. Dont know if it had a scew back or not.
He may shed more light on it it when He returns from Brother Dan Degarmos Funeral. Dan Passed away after a long illness with ALS. From FIT, Beta Nu Zeta.
Had the pleasure of meeting Him one time at BN.
Jono and I were guessing it might have been some sample type Pin before the one used today came into effect.