In countries like that - Costa Rica, Panama, etc.. - it is usually all the same. Money makes the laws. You find someone willing to take your money, you will find what you need if they have it. The question is - do they have it?
In Costa Rica you can easily obtain most recs and party drugs. But the only roids I have ever seen there were the 2mg winstrol tabs and single dose vials (1cc) of test. And there isn't a stock in those enough to make it worthwhile the trip.
I mean really... just look at the country and see how much of a demand for antiaging there is. Do you think most people in 3rd world countries are worried about some facial wrinkle or erectile dysfunctions? mexico is different because Hollywood and Venice Beach is right over the line and they have a good supply of Americans there. If the 51st state of the US were to come bordered on panama or such, you could expect their drug business niche to boom there too.