i was browsing a pawn shop on my lunch break today and i noticed a mario/duck hunt cart that looked different the the ones i have seen before.

on the sticker between the mario and duck hunt art there is the nintendo logo and the sticker has a blue-ish border. whats the story with this cart?

http://www.nintendoage.com/index.cfm?FuseAction=NES.Game&Game_ID=1588

Kinda like this? There's a few variants of this one. The one of which you speak is also notably missing the seal of quality. The only other games I can think of off the top of my head (licensed ones of course) that have this missing-seal variant are SMB2 and Donkey Kong Classics. The blue border you mentioned seems to vary in darkness, with some carts appearing close to black. I'm not sure if this has more to do with the production facility or just varying changes in the production process in no specific factory.

Hey, I have that one. :)

It's not rare, though, is it?

Ungodly rare, worth about .25 cents...give or take .25 of course :P  It is less common than the other version but I can go to my local flea market and buy 20 of each version any weekend.
~~NGD

Variants are tough to gauge rarity on, but of all the SMB/DH's that I've come across, I've seen multiples of each of the variants. I think the one pictured at that link is actually more frequent than the one with the white line dividing the middle...but only a ratio of 3 to 2 if my recollection serves properly. It makes sense as the one without a seal is the older cartridge, and was produced from the introduction of the Zapper all the way until the white oval seal started popping up, the period during which the lion's share of consoles were sold to consumers. Think about the availability of any recent console as a model (PS3 and Wii are still sold out, so for example, PS2). They were (and are!) still selling brand new PS2's but never so many as the first five years.

There's actually a sub-variant of the later one, a copy that has the oval seal with a small (tm) at its corner, and one that has the final seal version with the (r) notation instead. I have seen slightly more of the (r), which possibly is justified by the (tm) being used in a shorter transition period after the original black round seal was retired. I'm not sure of the last date the action set was released, but I've got an action set box with the very late red bar along the top, used only after the SNES had been released 1991/92. I need to do some more pinpointing to find a range of dates between which the TM was used before (R) started showing up. This info is also useful for finding out which other carts may have this sub-variant. I've got a vague idea but I think it's possible to pinpoint the month, and I'm willing to wager it's at the start of a sales quarter.

Anyways, there's the minutae hiding on the surface of your R1 staple. I'm not a hardware guy but I'm sure there's even more inside :)

...of course I defer to the higher power though :)