Yep, almost certainly helical cut bevel gears, one on the output shaft of the engine, an larger idler perpendicular to the engine shaft whose axis of rotation is on the axis of tilt, and the third on the input to the prop shaft. The wiki article describes the engines as "geared", and that ratio could be incorporated into the bevel gears.
If the props were cross coupled then there may also have been some sort of clutch mechanism on the engines' output. Depends if the cross coupling was to ensure that both props had the exact same power input, or also to make an engine failure more survivable (in which case you'd want to be able to disengage the failed engine). Given that it was an experimental aircraft such niceties may have been left for production designs.