Since the seed is no longer displayed by default in the world creation menu, the rules for Random Seed have been changed to the following:

• You must mouse over the seed icon after generation, before entering the world or leaving the worlds menu. If the seed is randomly created and displayed on screen before generation, this rule does not apply.
• On versions 1.4 to 1.4.4.9 the seed is filled out automatically - leave it unchanged. On 1.4.5 the seed may be randomized with a special button before world generation.

Checking the seed after the run does not guarantee seed integrity and would therefore not be enough to comply with the rule.