Does verb-てあった mean the same thing as verb-てあります?
To answer your question simply, the two forms you are asking about do not mean the same thing.
You've actually got two differences at work here.
One difference is the politeness level. ~てあった, is the plain form. ~てあります is the polite form.
The other difference is the tense. ~てあった, is the past tense. ~てあります is the present tense.
I hope that helps clear it up.