The sheadings are now significant only as :
The sheadings are only significant now :

Are these two sentences paraphrases of each other?
yes

Irregular verbs are like the participle Perfect very predictable , but regular verbs ( mainly the second conjugation ) are many .
Like the past participle , regular verbs are very predictable , but many verbs ( mainly of the second conjugation ) are irregular .

Are these two sentences paraphrases of each other?
no

With the activation of the 310th Strategic Missile Squadron , 310th on March 1 , 1962 was renamed the 550th Strategic Aerospace Wing .
With the activation of the 310th Strategic Missile Squadron , the 310th was redesignated as the 550th Strategic Aerospace Wing on 1 March , 1962 .

Are these two sentences paraphrases of each other?
yes

Sometimes already assigned codes were re-used or the x00 codes spared previously were allocated .
Sometimes already allocated codes were reused or the previously spared x00 codes were assigned .

Are these two sentences paraphrases of each other?
yes