The International Ladies' Garment Workers Union (ILGWU) wants Harvard to boycott the company that manufactures the caps and gowns students wear at Commencement, but it isn't sure whom to ask.

David Rosen, an attorney for the union, said last week it had sent a letter to the dean of Harvard College requesting a boycott of Cotrell and Leonard, the Albany, N.Y., cap and gown manufacturer. But neither Dean Fox nor other officials said they had received such a letter.

Rosen said yesterday the union has also mailed the letter to the Harvard Coop, which acts as Cotrell and Leonard's agent in supplying Harvard students with the regalia.

James Argeros, Coop general manager, said yesterday he had not heard of the labor dispute at Cotrell and Leonard and had not received any letters from the ILGWU. He said he could not predict whether the Coop would join a boycott, but added, "Our principal concern is making sure we have the caps and gowns in June."

"The Coop is just an agent for Cotrell and Leonard--it's their business," Frank Maguire, the Coop purchasing agent who deals with the company, said yesterday.

The union and Cotrell and Leonard are entangled in a four-month labor dispute. The union has charged the company with unfair labor practices and called two strikes, one of which is still in progress; the company denies the union's charges and says both the strike and the complaints are the work of only a small group of employees. The National Labor Relations Board has scheduled a hearing on the case for next February.