So did this bond hit final maturity in 1974, or face value in 1974? IIRC, a series E-bond was purchased for 75% of its face value, paid interest for 30 years from its issue date, and usually hit face value in about 5 years, give or take? So it would have hit its face value of $100 roughly 5 years after it was issued, and then continued to pay interest above and beyond that until 30 years after it was issued. I'm sure it's worth a pretty tidy sum by now.
My Mom used to take out savings bonds for me back in the 70's, starting soon after I was born. I think she quit sometime in the early 80's, and then she put them away and forgot about them. Until she realized how fast time went by, and that some of them might have hit final maturity. So she gave them all to me back in 2003, meaning that some of them had hit final maturity 3 years earlier.
In checking my records, I see the oldest bond I had was a $25 E-bond purchased for $18.75 in June, 1970. When I redeemed it, it was woth $138, or roughly 5.5 times its face value. I cashed in all of the bonds that hit final maturity, and since then have been going to the bank roughly 4 times per year to redeem more as they hit final maturity. So far, it looks like they've been getting between 5 and 5.5 times what their face value was. So I'd imagine that $100 bond is worth between $500-550?
