Receptor binding studies on sarbecoviruses would benefit from an available toolkit of recombinant spike proteins, or domains thereof, that recapitulate receptor binding properties of native viruses . We hypothesized that trimeric Receptor Binding Domain (RBD) proteins would be suitable candidates to study receptor binding properties of SARS-CoV-1 and -2 . Here we created monomeric and trimeric fluorescent RBD proteins, derived from adherent HEK293T, as well as in GnTI-/- mutant cells, to analyze the effect of complex vs high mannose glycosylation on receptor binding . The results demonstrate that trimeric, complex glycosylated proteins are superior in receptor binding compared to monomeric and immaturely glycosylated variants . Although differences in binding to commonly used cell lines were minimal between the different RBD preparations, substantial differences were observed when respiratory tissues of experimental animals were stained . The RBD trimers demonstrated distinct ACE2 expression profiles in bronchiolar ducts and confirmed the higher binding affinity of SARS-CoV-2 over SARS-CoV-1 . Our results show that complex glycosylated trimeric RBD proteins are attractive to analyze sarbecovirus receptor binding and explore ACE2 expression profiles in tissues.