  We perform analysis of the near-threshold $J/\psi $ photoproduction data off
the proton based on the high skewness expansion ( $\xi \to 1$) of the
cross-section in Ref. [1]. This expansion allows to separate the corresponding
gluonic form factors, in much the same way as this is done in the
electro-magnetic case with the Rosenbluth separation. We examine the
independence of the extracted form factors with the photon beam energy. In Ref.
[1] these form factors, in the leading-moment approximation, are related to the
proton's gluon Gravitational Form Factors (gGFF). Using this approximation, we
compare the extracted data points with lattice calculations in the region of
momentum transfer squared of $1<|t|<2$ GeV$^{2}$, where the data and lattice
results overlap. Such analysis demonstrates the possibility of extracting some
combinations of the gGFFs from the data at high $t$, complementary to the
lattice calculations available in the low $t$ region. However, higher
statistics is needed to more accurately check the predicted $\xi$-scaling
behavior of the data and compare with the lattice results, thus testing the
theoretical assumptions used in Ref. [1].
