Yes, totally normal. By 6 months old the biggest growth is over, and most puppies will scale back their food by half or even more.
Two cups total per day, per dog, is about right for most adult goldens.
Gibson's Golden Girl, CD, CGC, TDI (born 3-20-1997), a.k.a. "Tiny"
CH Rosewood Little Giant, UDX VER RA SH MXP MJP VCX WCX CCA CGC FFX-OG (born 3-10-2007), also UCH HR UUD UJJ URO1 UHIT a.k.a. "Tito" (the Tito Monster)
and my heart dog
Gibson's Golden Guy, CD, CGC, TDI ( 01-31-1998 - 01-02-2012) a.k.a. "Toby", "HRH"