To answer simply, no the Zone doesn't support gains in its normal form. You have to add blocks of protein and fat to do it. Personally if you want gains in strength, you should give up the Zone and eat.
As much as people want to say otherwise, the Zone is touted and works great as a weight loss diet. It works ok as a maintenance diet. It works horribly (in my humble opinion of 2 years playing around with the Zone and IF in my own life) as a mass/strength gain diet.
2-5x fat works ok for maintenance. But if you just ate normally without the Zone....you'd be eating pretty darn close to the same way you would as the Zone with extra fat blocks. You just wouldn't have to go through the pain of measuring things.