The Acharyas should serve and worship the Murtis of God installed in the big Sikhar-Bandha temples as well as the smaller temples and Havelis, by Lord Swaminarayan himself. He mentions Laxminarayan here simply because he wrote the Shikshapatri in Vadtal and so the idols of Laxminarayan, who preside in Vadtal temple are remembered.
This does not however imply any superiority or inferiority of any of the forms of God installed by Lord Swaminarayan, and so all other forms - Narnarayan, Gopinathji etc. should all be equally worshipped. All such forms should be served with love as explained by Vithalnathji, in accordance with Vedic rites.
Shatanand explains that this precept applies to all as God has said, ‘Serve me with respect, bowing before me surrendering all parts of their body and serve in temples like a servant’, thus specifying the ideals of a Bhakta.
Lord Swaminarayan during his stay upon the Earth built six major temples, installing various forms of God in them. At Ahmedabad and Bhuj he installed Murtis of Nar-Narayana. At Vadtal, Laxmi-Narayana as well as an image of himself called Hari-Krishna Maharaj were installed. Madan-Mohanji at Dholera, Radha-Ramana at Junagadha and Gopinathji Maharaj at Gadhada were installed by the Lord.
These are the presiding deities at each of the six temples. Along with these, Murtis of Radha-Krishna, Dharma-Bhakti, Surya-Narayana, Siddheswar Mahadeva and others were also installed. Therefore service of such forms of God has been advocated here.