Anything unusual of squawk 0143 for MH17?
 

MH17 was squawking 0143 at July 17.
I understand this squawk is part of a range used for experimental activities.
Wikipedia says:
Allocated to Service Area Operations for assignment for use by Terminal/CERAP/Industry/Unique Purpose/Experimental Activities (USA)[15]

Is this squawk unusual?

Anything unusual of squawk 0143 for MH17?
 

The aircraft was not in American airspace, so your cherry picking of a publicly-edited website in any case is not valid. Just because a set is reserved in one country does not hold true in another.

Best example therein, conspicuity is 1200 in the US, and 7000 in the UK.

According to the Code Allocation in UK IAIP ENR 1.6-8 SSR Code 0143 is from code block 0140-0177 'Transit (ORCAM) Amsterdam' (ORCAM being 'Originating Region Code Assignment Method'). SSR Code 0143 is not unusual.

0143
EU and UK ORCAM Amsterdam Centre

No doubt different in Ukranian airspace

Ukraine is an ECAC state so you would expect it to use the EU ORCAM codes at least on entry into Ukraine airspace.

where no conflicting code is in the system the ORCAM code is retained.

Google EUROPEAN SECONDARY SURVEILLANCE RADAR (SSR) CODE MANAGEMENT PLAN - appendices A & B for maps of the areas involved