There is really no standard on how long a shed will last in the woods.( just my opinion, it depends on the rabbit,squirrel and rodent population) I have found large #s of older sheds with little to no chew marks on them on a property with a low rodent population. I have found very old sheds on my mothers mountain in montana that had never been chewed on by animals, and I have found antlers on land with a high rabbit,squirrel,rodent population that were just about chewed in half with the G2 and G3 completly chewed off down to the main beam in less than 1 year from the time of shed.Your shed could of come from your buck( anything is possible) or it could be from another buck with basically the same genetic lines and traits for antler development.( close relative) I will take into account the dryness and coloration of an antler when trying to age it. I look at the base of the antler where it attaches to the skull a fresh antler will still look white and moist with small spots of fresh red blood on them, as they age the base takes a bit of a hard white dry apperance with any blood having turned brown( looks like a piece of sulphur that you find near the hot sulphur spings in yellowstone) with the texture of hard sandpaper.The antler coloration that a antler turns with age depends on enviromental conditions. A antler exposed to lots of like will bleach out white,or grayish white an antler exposed to lots on sunlight but laying in a moist area will bleach on top and take on a a coloration of yellowish ,gray ,dark brownish purple on the bottom.Some I have found sheds in the big old hard woods full of old oak woods etc that looked fresh that were actually 1 year old. Their can be so many varying envirormental factors that can contribute to the coloration of a antler.( so much can vary due to the difference in the types of woods a buck is rubbing also)The above are just some basic guidelines I use for a start in my area.Yes I believe that the 8 could be a 10 this year. Alot of times a buck shed that I find will have just a small little bump or thicker spot in the antler where I would expect to see a future tine growth will have the following year a new tine in just that spot when I find his new shed. Hope this helps ya some.