New theoretical expressions are devised employing a dynamical perspective for photoionization cross-sections differential in electron ejection angles for both fixed-in-space and randomly oriented molecules, and comparisons made with K-shell ionization measurements in molecular nitrogen. Closed-form, cross-sectional expressions are obtained in the dipole limit in terms of molecular body-frame transition moments and related normalized angular-distribution amplitudes which can be calculated employing interaction-prepared states without reference to specific scattering boundary conditions, and which reduce to more familiar atomic expressions in appropriate limits.