Bicentenial Sheet Without Denominations

I found one of the 1976 Bicentenial sheets that is postmarked but no denominations on each stamp of the sheet. Was this a give-away at the time? No 18 cents printed on the stamps.
No gum on the back. (Scott #1687)

Dave

Can you post an image of the sheet?
Don

I've never uploaded a px so hope this works.

Bicent sheet with no denominations.

Dave

It is not a freebie, it is an error assuming the denomination is completely missing from any of the stamps (because of the colors used it is hard to see the denomination when it is there).
It has a First Day cancel and I seem to recall some of the errors are known with a FD cancel.

Look closely....18c is there

I can definitely see the 18c/USA on 1687d ... and I think it's probably present on the others as well. Location on a thru e is: lower right, upper right, upper left, lower left & upper right respectively. Hard to see unless sheet/stamp is held at an angle to the light source. The postal service could have used an easier to see color for the 18c/USA.on these.

OH! You are right. I see it now, the 18c, with the light across the stamps and a magnifier. At my age I'm lucky to see anything. Thanks for pointing it out.
Dave in Portland

Fun facts: The Bureau of Engraving & Printing, treasury dept. Washington D.C. who printed this issue, originally wanted to apply the denominations (& "USA" I believe) with an intaglio press (recess-engraved, like the raised printing on real U.S. currency). But there were so many difficulties in trying to pull that off that it was abandoned, and they had to use a photogravure press unit anyway. It was at that point that someone should have spoken up about the colors blending in too much to the surrounding colors and ask approval for different colors. (I've observed there are also better locations within the intended perforations that would have made the "USA" and cents value a LOT more readable !!) But they were in a rush for the entire project anyway...
(b) At least one set has been listed on ebay as 'error' -- denomination color missing! But even with the image that came through on ebay's website, you could see the denomination... so much for yet another seller not looking at their own listing to see what they are asking buyers to put up with... I told the seller and they promptly agreed they could see, too with a re-look and they ended the listing.