As H.G. is starting up the time machine, there's an object just behind Rebecca that matches the design for the flux capacitor from the DeLorean of Back to the Future (1985).
The maximum duration of the trip through time is 22 hours and 19 minutes. This totals 1339 minutes, which is perfectly divisible by 13.
When Myka asks "What about the butterfly effect?" it is not a reference to the popular - and false - inference from Chaos Theory that a butterfly in the Amazon could cause a hurricane somewhere. Myka says "...when you step on a butterfly in the past and it changes the whole future... ".
It actually refers to the story "A Sound of Thunder" by Ray Bradbury, wherein a dinosaur-hunting time traveller makes that tiny change - crushing a butterfly - far in the past and causes huge changes to the "present".
In 1961, Charlie states that the Warehouse agents are getting close to obtaining Man Ray's camera, which was finally added to inventory earlier this season in "Age Before Beauty".
This is the third mention of "Gus", a previous Warehouse agent "lost" by Mrs.Frederic.