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The DA Form 638 is a valid source document for promotion points and therefore is a valid source document to update your ERB.
AR 600-8-19 (Enlisted Promotions and Reductions), par 3-46c(1)(a):
(a) List all awards, decorations, and achievements individually that the Soldier has earned. All entries for awards and decorations must include award number and order number (example: AAM 2OLC, 97–023). DA Form 638 (Recommendation for Award) or the awards certificate may be used as a source document provided it contains the ending period, the orders number, and the orders date. All achievements must include date awarded (example: Certificate of Achievement, YYYYMMDD; Soldier of the quarter, YYYYMMDD). Award points according to the scale in this regulation.