Yes, spices at bottling is pretty typical. A good rule of thumb to go by: anything with starch or oil goes in the mash eg. pumpkin, any adjunct that you want flavor or aroma from goes in late boil or secondary eg fruit, honey, dry hops. Anything particulate like spices goes in at bottling. Obviously there is room to play with these. I put the coffee in my coffee porter during cool down and pull it out before the wort goes into the fermenter. Many put it in the secondary. Bottling makes adding spices easy too because you can boil them in with your priming sugar. Just be careful you don't boil too hard or you'll end up with a goopy mess.
Oh and the contribution of anything from pumpkin in beer is pretty negligible. Every year I go into my LBHS to brew a pumpkin ale, the owner always shakes his head at me that I add pumpkin at all. For me, I don't know I could morally make a pumpkin beer with no pumpkin in it, but he's right. The flavor we all perceive pumpkin to be is not the pumpkin, it's the spices in the pie we make from pumpkins.