Sorting out Experimental Airworthiness Certification and LSA designation

I have a glider manufactured in 1998 in Poland and imported to the USA in 1999 and issued an Experimental Airworthiness Certificate. It is type certified in Europe. (SZD 51-1)

The glider appears to meet all of the operational specifications for LSA wrt weight, VNE, stall speed etc.. Is that sufficient to make it an LSA for FAR purposes? Is it necessary/possible to amend the Air Worthiness Certificate to designate the glider as an LSA? Is there any particular advantage/disadvantage to doing this?

Why would I stir the pot?

I bought the glider used. I moved it to a new base of operations. The original operating limitations required flying within 300 NM of the previous location. Last year, the local FAA office was happy with a program letter specifying my 'temporary' base of operation. This year they want me to amend my airworthiness certification and change my base of operations. They tell me that an inspection is not needed to amend the certificate.

Why do I care about LSA? I would like to get rid of the 300 NM geographic radius limitation and also eliminate the need for a program letter whenever I want to fly outside that radius. I'm wondering if I can ask for this amendment to be made at this time and whether the LSA designation would help me.