the English is not clear at all, but that would appear to be what they mean.

I know it's too late now, but just for future reference:

Although as Anna says, 'from' would read more easily here, in fact it's not incorrect to use 'of', inasmuch as (just as Carol has already said) we do often says 'within 2 months of'

However, the point I really wanted to make is that whether you use 'within... of' or 'from', the original meaning is actually ambiguous anyway, and only the rest of your context might make it clear.

'till 2 months from' COULD mean 'till 2 months after' — BUT it could equally well mean 2 months before; it all depends on what is happening here, and which makes most sense. Logically, of course, one would take the date it is signed, and then wait 2 months. But don't forget, the opposite is also possible, though hopefully, less likely: 'changes may only be made to the specifications till 2 months prior to the signing of the contract (after which time, everything will be fixed)'

So you see, while the original EN is not very smoothly written, it is also ambiguous!