Welcome to the forum , gibbybabba .
It would be highly unlikely for a sterling silver item of this type , size & era to be unmarked .
You might want to double-check with a magnifying glass for any marks , especially for numbers like - .850 , .900 , .925 - if you're looking for sterling silver .
Many items of this type were made of 'spelter' , pewter , lead compunds , etc. ..... and were sometimes plated with a variety of metals as well .
If you use search terms like -'vintage rearing metal horse figurine' or 'metal rearing horse figurine' on an Ebay search , you'll see what common 'asking prices' are listed .