Wearing a beard in dress blues, retired , @ funeral. Can it be done ? Or is it against regs or is it just going to piss-off vets ?

670-1 states that you wear the uniform as an active duty Soldier....b. All persons wearing the Army uniform will wear awards, decorations, and insignia in the same manner as prescribed in this regulation for active duty Soldiers. SO Para 3-2 (b) would also apply to us retirees..(b) Facial hair. Males will keep their face clean-shaven when in uniform.
Unless you claim a religious accommodation: 3:16 b. Beard.
(1) Beards (which include facial and neck hair) must be maintained to a length not to exceed 2 inches when measured from the bottom of the chin. Beard hair longer than 2 inches must be rolled and/or tied to achieve the required length. Beards must be worn in a neat and conservative manner that presents a professional appearance. Soldiers may use styling products to groom or hold the beard in place, but may not use petroleum-based products if wearing a protective mask during training. The bulk of a Soldier's beard may not impair the ability to operate an assigned weapon, military equip-ment, or machinery.
(2) A mustache worn with a beard may extend sideways beyond the corners of the mouth to connect with the beard, but must be trimmed or groomed to not cover the upper lip.

Short answer is no, SGT. Unfortunately. You do need to be in compliance with AR 670-1 when wearing the army uniform

SGT Raymond Balzano Here is a previous post that answers your question.

https://www.rallypoint.com/answers/can-a-veteran-wear-their-service-uniform-with-facial-hair