Hello all! I recently purchased a bulk lot that contained a couple of old albums. There were some Special Delivery stamps mounted. One of them was labeled an E5 but when I checked for a watermark, I didn't see one. This leads me to believe it is either E1 or E2. How does one differentiate between the two?
E1 reads SECURES IMMEDIATE DELIVERY AT A SPECIAL DELIVERY OFFICE
E2 reads SECURES IMMEDIATE DELIVERY AT ANY POST OFFICE
E4 has a dark blue line under the words TEN & CENTS (the line is not found on E2)
E5 same as E4 but watermarked 191 (double line letters)
