Sol:
I'm sure you can get suckling pig at Botin anytime. My reference to Botin being a second class restaurant had nothing to do with the quality of the food or service. The government for many years had a system of rating restaurants and hotels according to a number of factors--mostly the luxuriousness of the physical accommodations--not the qaulity of the food.
At one time (I don't know if this is still in effect) the prices a restaurant or hotel could charge were limited by its classification.
I'm not up to date on Botin's hours. I would think that between 1 and 2 o'clock would be about right.
If you have a dining partner, I suggest one of you try the cuchinillo, the other the cordero asado, and sample both.
My impression is that Botin has always been a consistently good restaurant, but you can find better. Restaurants abound in Madrid. But then I tend to be picky. IMHO it's as good as any place to begin your culinary exploration--and better than some. Ask for a table downstairs in the cave-like "bodega." That's where the ambience is.
Cantabene