Modelling transistor V_be and bulk resistance
The offset voltage can be modeled with different Is, as you suggest.
The Rbe, usually, is dominated by Rbb (the base spreading resistance); in
low-noise transistors (high beta) this will have less effect, so
you might want to use beta-selected transistor pairs in order to make this
parameter predictable.   So, it's Ib * Rbb...

In transistors intended for high-ish currents (500 mA and up) it is
not unusual to see deliberately added emitter resistance (it prevents
hot spots).  And, in PNP transistors (because N material has higher
mobility) the Rbb value might be smaller than in NPN ones.

Two manufacturers  may use the same name, but don't always make the same transistor.
Even from a trusted manufacturer, a geometry or process change can happen without
notice.  It's safest to avoid using off-datasheet info.