OK, so it looks like the whole model number is necessary on these love units as they have a myriad of options. I emailed technical support at Dwyer and they were very helpful:
The 16B-53 has two outputs. The first number 5 designates that output 1 is a current output, and the second number 3 designates that that output 2 is a relay output. Since output 1 is a current signal, you should expect a 4-20mA output instead of a voltage signal. The option for a voltage output would be a 2. For example, a 16B-22 or 16B-23 would both have a voltage signal on output 1.
I will test this out tonight but it looks like hooking up to output 2 should net the desired result.