One more SR question-

[FirstTimertoDiz]

This may be a stupid question, and I am sorry if it has been answered before, but when we sign up for offers, exactly how far do we have to go into the sign-up to get credit? I see that some offers say "zip code" or "fill out first 2 pages," but for the ones that don't list things like this, how do we know?

Just for an example, the one for free savings bonds- ID 235.

Thanks so much!