WASHINGTON, D.C., Feb. 19--The Selective Service could institute a random selection system before the June 30 expiration date for graduate student deferments, Lt. Gen. Lewis B. Hershey said in an interview today.

Hershey said that he could have a lottery operating within three to four months if Congress gives its approval to a specific random plan.

Any such random plan would involve drafting of a much higher proportion of 19-year-olds to older men than the recently announced policy of drafting the oldest first. This would mean that fewer seniors and first-year grad students would be drafted.

[Sen. Edward M. Kennedy (D-Mass.) announced Sunday that he would introduce legislation in Congress this week to completely revamp the draft system. Proposals include: a national lottery, liberalizing requirements for C.O. status, drafting youngest, first, reorganizing draft boards, abolishing punitive re-classification, setting a six-year term for Selective Service director.]

Hershey flatly denied charges that he had made it known Friday that he could not administrate proposed alternatives to the present selection system.

"I never said I couldn't do it," Hershey said, "although I did say it certainly would have been bedlam had we switched to any multiple age-group system."

He also said that the suspension of the essential activities and critical occupations list should have little effect on the number of occupational deferments granted.

He noted that half the men presently holding II-A's do not have jobs included in the now-defunct list. "The list was always a guideline, not law," he said.

Because of this, Hershey questioned the prediction that nearly all of this year's able-bodied male and first-year graduate students would be drafted.