Stamp ID Help Please

so over my long 2 week christmas vacation, my plan is to identify and mount a few of my smaller collections (of which I hold between 10 and 100 stamps). My procedure goes thusly ...

1) lay out stamps, examine to see if there is a date on the stamp which makes locating and identifying much easier.
2) open my 2008 Scotts to the right country, find the easy stamps, and then look for the ones with no year on them.
3) come back and print Will Steiner's album pages ...
4) mount and place in binder ... be happy

today I started with Mauritania ... 20 or so stamps and I found them all except for one (that seems to happen a lot)

can anybody help with a year or Scott id# for this stamp? The overprint seems to indicate a 1969 stamp ... but I cannot locate it in my catalog. Thanks so much in advance.

Hey there clifhiker.
Your stamp is SC#426, a 1977 stamp (#353) issued for the Viking Mars mission, reissued in 1979 with the overprint to honour the 10th anniversary of the Apollo moon landing.

thanks James ... can't figure why I couldn't see it, was right next to some other issues I had. Found it easily enough on Steiner's album pages.

polished off my Mauritania collection with a little assist, knocked out 20 stamps from Greece with only a little hitch (an overprint from occupied territories ... which I neatly dodged by mounting it next to its counterpart in the general section ... cheating I know ;-)). Started on my Ireland stamps, another 25 mostly definitive very nice stamps. Ran into a problem that I'm sure that the experienced worldwide collectors have seen before ... which is why I'm here asking. I have identifies all the ones like the stamp on the left with the dog on the brooch ... am having trouble with the one and only Stag stamp ...

Here are the stamps ...

and here is my question; the Scott says on the original 1968-70 description "1sh12 Stag on ancient bowl" and on the 1980-82 reprint "Type of 1968 13p, 16p stag; others dog" ....

Never mind I figured it out! The green stag stamp is a 1976-79 issue! What fun to unravel some of these definitives!