I'm going to show my ignorance now. What's a stockpot exactly? Not sure either of my local butchers do one - and wouldn't even know what to ask for.
It's a small plastic pot, about the size of a single trifle or yoghurt pot containing a stock in jelly form and with a layer of lard or dripping over the top to seal it. Something like this.
My butcher has less dripping and more stock and the stock is black so it looks a bit like Guinness. Another butcher i go to, there is a bit more dripping and the stock is more of a brown colour.
Definitely worth asking for for non-spicy meat/gravy dishes.