Generally Siamese are pretty social creatures. Although often they do seem more emotionally attached to their people than to other cats, usually a 2 year old meezer would enjoy having a playmate. Of course every cat is an individual so there's no guarantee of how it will work. but the chance of it working is much higher if you do the introduction carefully. Keep the new cat or kitten in its own room for a week or two, and swap items with their scents to let them get used to each others scent, and to their scent blended together, before they ever meet face to face. Then you can start things like feeding them on either side of the closed door.
When you do let the newcomer out, at first you can have it just be for short supervised visits out of his room, and see how it goes. It's natural for there to be some hissing and posturing at first. but hopefully they'll work it out . Make sure throughout the process, you are giving your current cat a lot of attention.
One thing I recommend is when you're talking to whomever you get your new cat or kitten from, whether a responsible breeder or a rescue group, tell them ahead of time that you will make every effort to make it work & take their advice about that, but if several months go by and it is not working (violent fights or cats being extremely stressed), then you will need to be able to return the new cat. Any good breeder or rescue will take back a cat that came from them ( that should be in their contract ) , and they will respect you for saying that your FIRST responsibility is to the pet you already have..
Hopefully they'll get along fine and that won't be necessary anyway.
While 2 mature intact toms usually will fight terribly, 2 neutered males is a great combination. So I say go for it!
years of experience of Siamese as well as Siamese mixes & pointed domestics , and integrating cats